The problem with this well known tool is that in making the lengthwise cut, the force necessarily applied to the handle tends to overcome the spring allowing the cable clamp to move away from the handle as the handle tilts to a position inclined to the cable, instead of being perpendicular to the cable, and the cutting blade then loses part of its penetration and makes an imperfect slit, which may not enable the peeling operation to be satisfactorily performed. The object of the invention is to solve this problem.